IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask A Report A-D3b, Date: December 2010
The Figure 10 shows that the data scatter a lot for the different months and systems. There
are some values of 0; this means that the value was not measured for this particular system
and this particular month.
The reasons for scattering data are on one hand different weather conditions in the different
locations and months as well as the different technologies. The systems in Perpignan and
Graz use dry heat rejection systems with external spraying. The other 3 systems use wet
cooling towers.
Water consumption, L per kWh
dissipated heat
3,5
3
2,5
2
1,5
1
0,5
0
Jun Jul Aug Sep
Perpignan 2009 Graz 09/10 Butzbach 2009 Gröbming 09/10 Gleisdorf 2010
Figure 10: Water consumption of cooling towers per unit of rejected heat
On the other hand, the large differences between the systems also show that also in terms of
water consumption, many systems can still be optimized.
4 Conclusions
Within this task, 11 small-scale solar heating and cooling systems have been monitored in
great detail. All of them have operated and produced heat and cold reliably during most of
the monitoring period.
However, the performance figures vary significantly. Some systems show very good results
in terms of total electrical COPs as well as fractional primary energy savings. In some cases,
this is due to the fact that during the monitoring campaign the system has been improved in a
certain way.
Comparison of the performance figures revealed that all or most systems still have
optimization potential. Even the systems that have bad performance figure could very likely
be improved to reach good values.
The main optimization potential of most systems lies in the electricity consumption of certain
components such as pumps or cooling tower fans. On one hand, the selection of these
components is important. Energy efficient units should be chosen. On the other hand, the
control strategy especially if operated in part load can reduce the electricity consumption
significantly.
This monitoring campaign showed that
A good system design is important in order to reach good performance figures.
Monitoring of this kind of system is necessary to ensure proper operation because it
still is a relatively new technology. It enables the system supplier to further improve
the system during operation and to maximize primary energy savings of the system.
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